Air-to-air refueling drogue assemblies
An air to air refuelling drogue assembly includes a reception coupling and a drogue canopy connected to the reception coupling by connection means which hold the canopy in an operative, drag producing, position relative to the reception coupling during refuelling. The drogue assembly is arranged to controllably fail so as to reduce the drag load produced by the drogue when a drag load on the canopy exceeds a predetermined threshold.
1. An air to air refuelling drogue assembly comprising:
a reception coupling and a drogue canopy connected to the reception coupling by a connection arrangement which holds the canopy in an operative, drag producing, position relative to the reception coupling during refuelling, the connection arrangement comprising at least one tether element, at least one latch element, and a control arrangement for controlling the latch element, the latch element holding the tether element against release to keep the canopy in the operative position in normal operation and arranged under control of the control arrangement to release the tether element, when a drag load on the canopy exceeds a predetermined threshold, to at least partially release the canopy.
2. An air to air refuelling drogue assembly according to claim 1 in which the control arrangement comprises sensor means responsive to the drag load on the canopy.
3. An air to air refuelling drogue assembly according to claim 1 , in which the control arrangement is arranged to sense the load on the tether element held by the latch element and allow release of the tether element by the latch element when the load on the tether element exceeds a predetermined threshold.
4. An air to air refuelling drogue assembly according to claim 1 in which the latch element is arranged for movement between a holding position in which the tether element is held against release and a release position in which the tether element is released from the latch element.
5. An air to air refuelling drogue assembly according to claim 1 in which the control arrangement comprises a spring means.
6. An air to air refuelling drogue assembly according to claim 4 in which the control arrangement comprises a spring means and in which movement of the latch element between the holding position and the release position is controlled by the spring means.
7. An air to air refuelling drogue assembly according to claim 5 in which the spring means is connected to the latch element such that the spring means resists movement of the latch element caused by load on the tether element attached to the latch element.
8. An air to air refuelling drogue assembly according to claim 5 in which the connection arrangement is arranged so that the spring means allows movement of the latch member to the release position when the drag load on the canopy exceeds the predetermined threshold.
9. An air to air refuelling drogue assembly according to claim 1 comprising a plurality of latch elements each holding at least one respective tether element.
10. An air to air refuelling drogue assembly according to claim 9 in which there is a master latch element and at least one slave latch element, where the master latch element is controlled in dependence on the drag load on the canopy exceeding a predetermined threshold and the slave latch element is controlled in dependence on the operation of the master latch element.
11. An air to air refuelling drogue assembly according to claim 1 in which the canopy has at least two sections and the connection arrangement is arranged so that when the drag load on the canopy exceeds the predetermined threshold one section of the canopy is released to reduce drag, whilst another section of the canopy is retained in its operative position.
12. An air to air refuelling drogue assembly according to claim 4 in which the control arrangement comprises a retention member for holding the latch element in the holding position.
13. An air to air refuelling drogue assembly according to claim 12 in which the latch element is carried on a support with the support and latch element being movable together relative to the retention member between a position in which the latch element is held in the holding position by the retention member and a position in which the latch element is free to move without hindrance of the retention member towards the release position.
14. An air to air refuelling drogue assembly comprising a reception coupling and a drogue canopy connected to the reception coupling by connection means which hold the canopy in an operative, drag producing, position relative to the reception coupling during refuelling, wherein the connection means comprise at least one tether element, at least one latch element, and control means for controlling the latch element, the latch element holding the tether element against release to keep the canopy in the operative position in normal operation and arranged under control of the control means to release the tether element, when a drag load on the canopy exceeds a predetermined threshold, to at least partially release the canopy.